View Compilation Error

0_0_5237781_24272.cpp: In function `int main()':
0_0_5237781_24272.cpp:36: error: no match for 'operator-' in '(&S)->std::multiset<_Key, _Compare, _Alloc>::end [with _Key = int, _Compare = std::less<int>, _Alloc = std::allocator<int>]() - 1'